Open Access

Table 6

Experimental parameters used for closed-loop experiments with the iMZ.

Experimental parameters

iMZ WFS λ/D pinhole, 30/70 beam splitter
WFS wavelength 632 nm
Corrector 12 × 12 MEMS DM (surface: 4.4 × 4.4 mm2; pitch: 400 µm; stroke (1 actuator): 2.7 µm; coupling: 13%)
Controller Integrator with gain g = 0.3
Pre-corrected modes Piston, tip, and tilt

VLT equiv. Bench

Turbulence Atmosphere 512 × 512 SLM
Pupil diameter 8m 4 mm (1100 pixels)
dact 80 cm 400 µm (110 pixels)
r0 (0.6 µm) 50 cm 69 pixels
L0 30 m 4125 pixels
vwind 1.7 m/s 0.25 pixel/frame
Coherence time 94 ms 94 s
Frame frequency 1 kHz 1 Hz
Loop frequency 3 Hz ≈0.33 Hz

Notes. dact is the inter-actuator distance on the telescope pupil considered.

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